LEDs have been used in various applications, including illuminating watches, transmitting information from remote controls, and forming images on jumbo television screens. More recently, LEDs have been used in portable lighting devices (such as flashlights and headlamps) because, among other things, LEDs can last longer, produce light more efficiently, and be more durable than incandescent lamps commonly used in conventional flashlights and headlamps.
However, the brightness and expected life of an LED typically decreases with increased temperature. Effective dissipation of heat is therefore needed to maintain the temperature of the LED within its design limits.
Further, a limitation on many LED modules is the medium used to affix the LED to its supporting substrate. Current LED modules use a thermal epoxy or other similar substance. Thermal epoxies are difficult to work with and require extended cure times. LED attachments using thermal epoxies also have an increased incidence of premature failure.
Another limitation on many LED modules, especially those intended for use in flashlights and other portable lighting devices, is their inability to prevent operation of the lighting device when the power source (e.g., one or more batteries) are incorrectly aligned.
A further limitation on known LED modules, such as described in U.S. Patent Publication 2007/0058366 A1 (published Mar. 15, 2007), has been their relative complexity of assembly or manufacture.
Finally, another limitation on many LED modules used in portable lighting devices is their susceptibility to failure caused by electrical interruptions and/or shock from outside forces.
In view of the foregoing limitations on current LED modules, an object of the present invention is to provide an improved LED module that at least partially ameliorates one or more of the foregoing problems in the art.